Didn't manage to book a room at Paramount via phone, because when I called, there was always noone picked up the call.
However, my experience was with Sentosa KTV.
On last Thu, went to Sentosa for the first time (Paramount was full house) got a room, but a guy said the room was only available until 6pm. The reason was because it was a holiday eve, so he said everywhere the same, HH only until 6pm. I believe HH at Sentosa is 2-8pm, so what kind of non sense was this? Hence, we just went off and tried RS instead.
On last Reviewi, I called them when I was downstairs, asked whether they still had room, guy on phone answered yes. Then, I went up and asked again whether got room, they said don't have. WTF? Hence, it was very obvious that they were not willing to give us room.
All I can say is good luck to them if they keep doing their business in this way.